Ecological Resilience Glossary
The capacity of a system to withstand disturbances without changing function.
- Alternative Stable State
Alternative Stable State or Regime: One out of multiple different forms of existence or organization for a system; the system may transition to any of its alternative states if the appropriate environmental conditions are met.
- Ball-and-Cup Model
A conceptual model used to visualize and understand ecological resilience. This is outlined in detail in another module, however the visualization is of a ball, representing the current state of a system, on a 3D plane that has different “basins” or points at which there is concavity. This visualization is meant to represent the states a system is drawn to (the ball being drawn into a basin) and the potential for shifting from one state, or basin, to another with movement of the ball caused by perturbation.
- Basin of Attraction
Part of the ball-in-cup model. Represents a stable state in which a system can exist. The system can move from one basin of attraction to another, which represents a system shifting from one state to another. See regime shift
- Ecological Resilience
The capacity of an ecosystem to withstand disturbances without altering established processes, functions, and structures. This concept can be applied to other systems such as economies, governments, or companies, despite the term “ecological”.
- Ecosystem Services
Services and products that humans receive from ecosystems. For example, water filtration by wetlands, air purification by forests, food production by croplands, pollination by pollinators, etc.
When a change in one aspect of a system causes a change in an earlier aspect of the same system, whether positive or negative, and can be self-reinforcing. For example, rising temperatures can cause ice cover to decrease through melting. This exposes more land to the sun, which heats up the land near the ice and causes more melting, creating a positive feedback loop.
The general idea that the path out of a situation is different from the path you took to get into the situation. This can occur in ecosystems. See lake eutrophication example in the resilience and hysteresis modules.
The ability for components of a system to maintain relationships in the face of outside forces that cause change.
Perturbation (or Disturbance): An event or input to a system that causes a loss of the system’s capital. It may cause a regime shift. For example, wildfire in a forest, ocean acidification and coral reefs, woody encroachment in a grassland.
A state in which a system exists. Consider it as the status quo, which can be altered by forces that cause regime shifts.
- Regime Shift
Regime Shift (or Regime Change): The transformation of a system from one stable state to another. These changes often occur in response to disturbances. For example, a volcanic eruption on a Hawaiian island can shift a tropical forest ecosystem into bare volcanic rock.
- Threshold of Change
Threshold of Change (Tipping Point): The point at which a system shifts from one state to an alternative state.